In the early days of the telephone art, use of the telephone was often confined to communications among users within a local geographic area. As a result and over the years, the economies related to accessing a communications system have lead to telephones in a local area usually being interconnected through a central controller, often called a local central office in the art.
As digital computers came upon the scene, another local community of use was discernible. Hence, a central controller is commonly employed for interconnecting various user terminals, or stations. For example, U.S. Pat. No. 3,851,104; entitled "Digital Communications System" and issued Nov. 26, 1974; discloses a time division, multiple access communications system which, under the control of a central terminal, allows an interconnection among a plurality of user terminals by way of a single communications signal path.
As the digital computer art advanced, parallel advances in the semiconductor art lead to smaller, relatively inexpensive computers. With the advent of such smaller computers, the technique of central control is being abandoned in favor of a distributed control technique. Also, because of the usually bursty nature of digital computer information, the recent trend has also been toward communications systems having a capability for handling packets of digital information. One such distributed control packet communications system is disclosed in a copending application by N. F. Maxemchuk, entitled "System, Apparatus and Method for Controlling a Multiple Access Data Communications System Including Variable Length Data Packets and Fixed Length Collision-Free Voice Packets", and filed Mar. 15, 1982 as Ser. No. 357,850. Such systems commonly employ Carrier Sense Multiple Access/Collision Detection (CSMA/CD). Indeed, the copending application, inter alia, discloses a communications system in which, when a terminal (or a station or a source) is to start an intended packet transmission on a communications channel, the station listens to signals on the channel before transmitting (LBT). Upon detecting the presence of another transmission on the channel, the terminal delays the intended packet transmission until no other transmissions are sensed, i.e., it waits for an idle channel (WIC) and schedules a retry after detecting the busy channel (SRB). When the intended transmission is started, the terminal thereafter listens to signals on the channel, i.e., it listens while transmitting (LWT). If an interference (or collision) is detected, the transmission is terminated and a random number generator is used to schedule a retry after the collision (SRC) by selecting an interval of time at the completion of which a retransmission of the packet will be attempted.
Unfortunately electrically long CSMA/CD systems may introduce undesirable signal transmission delays.
Further, with the widespread introduction of cable television (CATV) and other relatively wideband systems, alternative uses for such wideband systems may be possible. In that connection, economical alternatives and/or adjuncts to the well known local telephone network are being proposed.